Case Report: A rare case of multi-vessel coronary artery-coronary sinus fistula combined with multiple coronary aneurysms initially presenting with frequent premature ventricular complexes

Coronary artery fistula (CAF) is a rare congenital coronary malformation. Sakakibara type B lesions, in which multiple coronary arteries drain concurrently into the coronary sinus (CS), are extremely uncommon, and cases initially presenting with high-burden premature ventricular complexes (PVCs) as the initial manifestation have rarely been reported. This paper reports a 63-year-old female patient presenting with intermittent palpitations for 1 year. A 24-hour ambulatory electrocardiogram (Holter) revealed a PVC burden of up to 40,804 complexes, with a total of 101,582 heartbeats recorded. Transthoracic echocardiography (TTE) demonstrated dilation of the left atrium, left ventricle and right atrium, moderate mitral and tricuspid regurgitation, dilated right coronary artery (RCA) with a right coronary artery-coronary sinus fistula, while lesions of the left circumflex artery (LCX) and second obtuse marginal branch (OM2) were missed. Three-dimensional coronary computed tomography angiography (CCTA) reconstruction showed tortuous and diffusely dilated LCX, OM2 and RCA, with aneurysms at the distal segments of all three vessels. The distal segments of the three vessels anastomosed with each other and drained into the CS. The dilated coronary arteries compressed the great cardiac vein, resulting in focal luminal stenosis. The patient's PVCs originated from the left coronary cusp. Radiofrequency catheter ablation completely relieved palpitations, and follow-up Holter at 3 months recorded only 1 PVC with a different origin from preoperative ectopy. Cardiac surgeons recommended surgical ligation of the fistula, but the patient opted for regular imaging follow-up and long-term clopidogrel antiplatelet therapy due to absence of myocardial ischemia, heart failure and other symptoms. This case indicates that three-dimensional CCTA reconstruction serves as the primary non-invasive modality for definitive diagnosis and therapeutic evaluation of complex CAF. Idiopathic PVCs originating from the aortic sinuses of Valsalva can coexist independently with CAF. Type B CAF with multiple feeding vessels draining into the CS represents a high-risk anatomical subtype, requiring long-term, individualized multidisciplinary management.